Java
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Java – JPA: @ primarykeyjoincolumn (…) and @ joincolumn (…, insertable =?, updatable =?) Same?
It can be derived from the JPA specification if there is no @ primarykeyjoincolumn (...) with pluggable and updatable …… -
Java – how do I get the hashtable value as an ArrayList?
Hashtable How to convert its value to: ArrayList <Word> arr thank you. Solution Use the ArrayList constructor t…… -
How to install the gson module in Java?
I downloaded the Google JSON module a.k.a gson I am a Windows system. Can you tell me how to install the gson module? …… -
Java – spring data dynamic query
I am using spring data to set up a dynamic query. Basically, I have an array with a series of features. I need to comb…… -
Can the Java – pluggable annotation processor API retrieve source code annotations?
I am using the pluggable annotation processing API with Java 6 to automatically create some deployment XML files Some …… -
Copying fields between classes in Java
I have a pair of classes. The field of one class is a subset of the field of the other. The getters of superset classe…… -
Java introspection – strange behavior
The following code is a small example that can easily reproduce the problem So I have a variable of type string and se…… -
Java – where to run complex algorithms? Server or client?
I'm trying to develop a social network Android application with a huge user database I am very new to android app deve…… -
Java – save files to SharePoint Server using jax-ws
I tried to save a file to a SharePoint Server using Jax - WS The web service call reports success, but the file is not…… -
Java – why is maptoint() not in the optionalint class?
The intstream class has map(), maptoobj(), maptolong() and maptodouble() methods, but these methods seem to be missing…… -
Java – how does akka implement the relationship before JMM?
In the official akka document, they refused: For details, please refer to the doc I wonder how akka did it I just pass…… -
Java – incompatible types and fresh type variables
I get the following compilation message: [javac] ... error: incompatible types [javac] exceptionClassHolder …… -
JavaFX – how to make ComboBox hgrow?
I have JavaFX (8), H@R_509_2419 @, Combo@R_509_2419 @And hgrow This is my fxml Code: <?xml version="1.0" encoding="…… -
Java – you can mark interfaces, such as serializable, which contains default methods?
I don't think it can, because the principle of markup interface is that there is no method, but I don't know because t…… -
Java – should you report the message text of the exception?
Consider some code that can throw a check exception (an exception of type exception) Of course, your code catches exce…… -
java – Make Enum. Tostring() localization
I'm developing an Android application and I want to know if I can set enum Tostring() multilingual I'll use this enume…… -
Java – when to use servicetracker and servicereference
I've just started using OSGi programming, and I've encountered two ways to listen to activated services The first meth…… -
Parallelism and plan view in Java 8 streams
Hey, I have a problem with parallelism when I use flatmap IntStream.of(-1,1).parallel().flatMap(i->IntStream.range(…… -
Java – why do you get a NullPointerException when comparing a string with null?
My code uses NullPointerException to break in the following line: if (stringVariable.equals(null)){ Before this statem…… -
java – com. w3c. dom. Document does not have
I'm using the following code to create com. Com from string w3c. dom. Document： DocumentBuilderFactory docFactory = D…… -
Java – LinkedHashMap signature
Looking at the JDK source code of LinkedHashMap, I notice that this class is declared as: public class LinkedHashMap&l…… -
Remote virtual machine using vagrant
I want to use vagrant to make the virtual machine run on a more powerful server than my laptop Can I use vagrant remot…… -
Java – Maven cannot find dependencies
I use Maven 3.1 Version 1 I'm trying to compile with dependency springs I see that this should exist in Maven through …… -
Java – get the metadata of the file
Can I know the metadata of a file through Java? If so, how to get the metadata of the file in Java? Solution You can g…… -
Java – “a value of type string cannot be opened below the source level..” error
I am using eclipse to develop a java program I had to downgrade JRE and JDK from 1.7x to 1.6 Now everything points to …… -
How does Java’s dynamic proxy actually work?
I know how to use dynamic proxies in Java, but what I don't understand is how VM actually creates dynamic proxies Does…… -
Java – how to set the ForeignKey name when I have @ manytomany
I am using JPA class to create database If we have a manytoone relationship, we can override the ForeignKey name, as s…… -
Java – JPA POJO as data object
What are the best practices for using JPA entities? Since the JPA entity is only a POJO, is it appropriate to use this…… -
Jpa-2.0 – the @ manytoone relationship cannot be empty
I have a one-on-one relationship and I want to be free: @ManyToOne(optional = true) @JoinColumn(name = "customer_id",n…… -
Java – ant waiting for file creation
Can ant be configured to pause the build process until the file is created (with a relative timeout)? Solution <wai…… -
Java – how to create a hazelcast instance embedded in process memory without networking?
In my unit test, I want to create an embedded (in-process / in memory) hazelcast instance that does not attempt to sta…… -
Integer in Java ParseInt, when ” is the first exception
Integer parseInt( “ – 1000”); Returns - 1000 as output Integer. parseInt(“500”); Throw exception How can we recognize ……